How to retrieve data from sqlite database in android and display it in TextView
I am learning Android. I have a problem and I can't solve it. I want to retrieve data from an existing database and display it in a TextView after click button.
My code DataBaseHelper looks like this:
public class DataBaseHelper extends SQLiteOpenHelper {
//The Android's default system path of your application database.
private static String DB_PATH = "/data/data/in.ekonomia.android/databases/";
private static String DB_NAME = "cytaty";
private SQLiteDatabase myDataBase;
private final Context myContext;
/** * Constructor * Takes and keeps a reference of the passed context in order to access to the application assets and resources. * @param context */
public DataBaseHelper(Context context)
{
super(context, DB_NAME, null, 1);
this.myContext = context;
}
/** * Creates a empty database on the system and rewrites it with your own database. * */
public void createDataBase() throws IOException
{
boolean dbExist = checkDataBase();
if(dbExist){
//do nothing - database already exist
}else{
//By calling this method and empty database will be created into the default system path
//of your application so we are gonna be able to overwrite that database with our database.
this.getReadableDatabase();
try
{
copyDataBase();
} catch (IOException e)
{
throw new Error("Error copying database");
}
}
}
/** * Check if the database already exist to avoid re-copying the file each time you open the application. * @return true if it exists, false if it doesn't */
private boolean checkDataBase()
{ SQLiteDatabase checkDB = null;
try
{
String myPath = DB_PATH + DB_NAME;
checkDB = SQLiteDatabase.openDatabase(myPath, null, SQLiteDatabase.OPEN_READONLY);
}catch (SQLiteException e)
{
//database does't exist yet.
}
if(checkDB != null)
{
checkDB.close();
}
return checkDB != null ? true : false;
}
/** * Copies your database from your local assets-folder to the just created empty database in the * system folder, from where it can be accessed and handled. * This is done by transfering bytestream. * */
private void copyDataBase() throws IOException
{
//Open your local db as the input stream
InputStream myInput = myContext.getAssets().open(DB_NAME);
// Path to the just created empty db
String outFileName = DB_PATH + DB_NAME;
//Open the empty db as the output stream
OutputStream myOutput = new FileOutputStream(outFileName);
//transfer bytes from the inputfile to the outputfile
byte[] buffer = new byte[1024];
int length;
while ((length = myInput.read(buffer))>0)
{
myOutput.write(buffer, 0, length);
}
//Close the streams
myOutput.flush();
myOutput.close();
myInput.close();
}
public void openDataBase() throws SQLException {
//Open the database
String myPath = DB_PATH + DB_NAME;
myDataBase = SQLiteDatabase.openDatabase(myPath, null, SQLiteDatabase.OPEN_READONLY);
}
@Override
public synchronized void close()
{
if(myDataBase != null)
myDataBase.close();
super.close();
}
@Override
public void onCreate(SQLiteDatabase db)
{ }
@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) { }
// Add your public helper methods to access and get content from the database.
// You could return cursors by doing "return myDataBase.query(....)" so it'd be easy
// to you to create adapters for your views.
}
Cytaty.java looks like this:
package in.ekonomia.android;
import android.app.Activity;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
public class cytaty extends Activity {
@Override
protected void onCreate(Bundle savedInstanceState) {
// TODO Auto-generated method stub
super.onCreate(savedInstanceState);
setContentView(R.layout.galeria);
Button bLosuj = (Button) findViewById(R.id.button1);
bLosuj.setOnClickListener(new View.OnClickListener() {
public void onClick(View v) {
// TODO Auto-generated method stub
}
});
}
}
I did as above and Eclipse gives me errors.
Database name: cytaty
name of table: cytaty
columns: _id, autor, cytat
My code is:
public void getData() {
public String[] getAppCategorydetail() {
String Table_Name="cytaty";
String selectQuery = "SELECT * FROM " + Table_Name;
SQLiteDatabase db = this.getReadableDatabase();
Cursor cursor = db.rawQuery(selectQuery, null);
String[] data = null;
if (cursor.moveToFirst()) {
do {
// get the data into array,or class variable
} while (cursor.moveToNext());
}
db.close();
return data;
}
}
And:
Button bLosuj = (Button) findViewById(R.id.button1);
bLosuj.setOnClickListener(new View.OnClickListener() {
public void onClick(View v) {
// TODO Auto-generated method stub
DataBaseHelper myDataBaseHelper = new DataBaseHelper(cytaty.this);
myDataBaseHelper.openDataBase();
String text= myDataBaseHelper.getData();//this is the method to query
myDataBaseHelper.close();
// set text to your TextView
TextView tekst = (TextView) findViewById(R.id.editText1);
tekst.setText(text);
}
});
}
What am I doing wrong?
I want retrieve data from database and show in TextView after click button. Your help would be appreciated.
on button click, first open the database, fetch the data and close the data base like this
public class cytaty extends Activity {
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.galeria);
Button bLosuj = (Button) findViewById(R.id.button1);
bLosuj.setOnClickListener(new View.OnClickListener() {
public void onClick(View v) {
myDatabaseHelper = new DatabaseHelper(cytaty.this);
myDatabaseHelper.openDataBase();
String text = myDatabaseHelper.getYourData(); //this is the method to query
myDatabaseHelper.close();
// set text to your TextView
}
});
}
}
and your getYourData() in database class would be like this
public String[] getAppCategoryDetail() {
final String TABLE_NAME = "name of table";
String selectQuery = "SELECT * FROM " + TABLE_NAME;
SQLiteDatabase db = this.getReadableDatabase();
Cursor cursor = db.rawQuery(selectQuery, null);
String[] data = null;
if (cursor.moveToFirst()) {
do {
// get the data into array, or class variable
} while (cursor.moveToNext());
}
cursor.close();
return data;
}
TextView tekst = (TextView) findViewById(R.id.editText1);
You cannot cast EditText to TextView.
You may use this following code actually it is rough but plz check it out
db = openOrCreateDatabase("sms.db", SQLiteDatabase.CREATE_IF_NECESSARY, null);
Cursor cc = db.rawQuery("SELECT * FROM datatable", null);
final ArrayList<String> row1 = new ArrayList<String>();
final ArrayList<String> row2 = new ArrayList<String>();
if(cc!=null) {
cc.moveToFirst();
startManagingCursor(cc);
for (int i=0; i<cc.getCount(); i++) {
String number = cc.getString(0);
String message = cc.getString(1);
row1.add(number);
row2.add(message);
final EditText et3 = (EditText) findViewById(R.id.editText3);
final EditText et4 = (EditText) findViewById(R.id.editText4);
Button bt1 = (Button) findViewById(R.id.button1);
bt1.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View v) {
// TODO Auto-generated method stub
switch (v.getId()) {
case R.id.button1:
et3.setText(row1.get(count));
et4.setText(row2.get(count));
count++;
break;
default:
break;
}
}
});
cc.moveToNext();
}